Numerous techniques and devices are known and available for sterilization of males or of females. Such techniques are frequently irreversible or, when reversal is surgically attempted, are not always successful in re-establishing flow of sperm through reconnected male ducts or passage of ova through reconnected female ducts. Moreover, where sterilization devices are surgically implanted, severance of the vas deferens (or other) duct of a male or of the fallopian tubes of a female is required. Reversal of sterilization effected by such devices may also require surgery. Difficulties and uncertainty are thus also encountered in re-establishment of fertility where known sterilization devices are used.
For example, U.S. Pat. No. 3,704,704 discloses a valve which may be surgically inserted within either the fallopian tubes of the female of the vas deferens of the male. Rather than permanently preventing conception by cutting (and/or tying) the vas deferens or the fallopian tubes, the disclosed valve spool is inserted in the cut duct. The valve spool may be completely closed to preclude passage of either sperm or ova through the respective tube, or may be opened by movement of a rotary element which is selectively movable to either the closed or open position.
However, in addition to the requirement for surgery to implement sterilization by cutting of the appropriate duct, reversal of the sterilization condition is effected by a surgical incision and insertion of a special tool to implement rotation of a rotatable element in the valve spool. Alternatively, external magnetic fields are contemplated for rotating a magnetically polarized element in the valve spool, coupled with X-ray verification. Thus, the patient is required to undergo at least one, possibly two, surgical procedures, along with exposure to external magnetic fields as well as to X-ray irradiation.
Another valved sterilization device, disclosed for use with the male vas deferens, is described in U.S. Pat. No. 3,777,737, wherein the vas deferens is at least partly cut transversely to form two separated sections with a ring barrier therebetween. The device includes a valve inserted between the separated portions of the duct, thus to prevent communication therebetween. The valve is inserted in the open position and, upon healing of the vas, is closed from the exterior of the body. Both closure of the valve and subsequent reopening, if desired, are effected by application of an exterior magnetic force to act upon an elongated bar magnet section of the valve.
Such devices are clearly susceptible to unintended effects of external stray magnetic fields, whether caused by geographical conditions or by modern technological devices such as magnetic resonance imagers. Accordingly, neither the sterilization effects nor the reversal thereof may be relied upon with complete assurance.
Other reversible sterilization devices are known which do not rely on magnetic fields for activation. For example, U.S. Pat. No. 4,682,592 teaches a reversible male sterilization device including a compressive plug, connected by a spring-like handle through an elongated tube and plunger to the external environment. The plug, which may be of rubber, foam or other compressible material which may expand under the effects of heat or moisture, is inserted to a proper position by a physician who then activates the plunger, withdraws the tube and disconnects a retrieval line from a hook on the plunger. Alternatively, an inflatable plastic cap is provided at the end of a valved hollow tube which fits within the male urethra. The tube is inserted by the user and a fluid injected to inflate the plastic cap thus to block the appropriate duct. After intercourse the device is removed from the urethra. Sterilization effected by the device is thus not reversible unless the device is withdrawn. Moreover, the complexity of the procedure appears likely to discourage widespread use thereof.
U.S. Pat. No. 3,918,431 discloses a surgical device for obturating fallopian tubes of a female to effect temporary sterilization. The device is positioned through the cervix using an endoscope and pneumatic insufflating means. A removable plug member is included to permit normal ovulation. The plug may be removed to uncover an opening establishing communication through the fallopian tube and thus to permit normal ovulation. At any time, the plug may be replaced, as desired. However, the disclosed plug element includes a magnetized hard metallic insert surrounded by a synthetic resinous sheath, serving as a tool retention means. Thus, although not relying on magnetic fields for operation, effectiveness of the disclosed device may be susceptible thereto.
The above described valve and plug devices require interaction among a plurality of components, including portions which are relatively movable with respect to one another. Thus, to attain reliable blockage of the ducts it is necessary to provide closely matched dimensional tolerances among the various components, whether movable or stationary. The resultant complexity of the known reversible sterilization devices accordingly increases the costs associated therewith and makes the same unaffordable precisely to individuals who, for economic circumstances, may wish to use sterilization devices. Accordingly, the difficulty and expense, as well as the discomfort and surgical risk, associated with implantation of prior art devices or with execution of known techniques frequently acts as a deterrent to sterilization.
Inasmuch as reversal of the sterilization effects of the above described devices or procedures, if at all possible, requires undergoing a surgical procedure, patients who contemplate subsequent childbearing are frequently deterred from undergoing sterilization. Instead, such patients rely on less effective devices for achieving birth control, such as interuterine devices, birth control pills, condoms and the like. However, such birth control devices are not as effective for preventing of conception and pregnancy as is complete sterilization.
There is thus a need in the prior art for a simple and inexpensive device for use in a reliable and effective non-surgical method for effecting reversible sterilization of males or females.